title: Compression ultrasonography for diagnostic management of patients with clinically suspected deep vein thrombosis: prospective cohort study.
abstract: OBJECTIVE
  To evaluate the safety of withholding anticoagulant treatment from patients with clinically suspected deep vein thrombosis but normal findings on compression ultrasonography.
  
  
  METHODS
  Compression ultrasonography was done with a simplified diagnostic procedure limited to the common femoral vein in the groin and the popliteal vein extending down to the trifurcation of the calf veins. Patients with normal ultrasonography findings at presentation were retested 1 week later.
  
  
  METHODS
  The incidence of venous thromboembolic complications during follow up for 6 months in patients in whom anticoagulant treatment was withheld on the basis of normal results on two ultrasonography tests 1 week apart.
  
  
  METHODS
  University research centres in four hospitals.
  
  
  RESULTS
  A total of 1702 patients were included in the study. Abnormal results on compression ultrasonography at presentation or at 1 week were found in 400 and 12 patients, respectively, for a prevalence of deep vein thrombosis of 24%. None of the patients were lost to follow up. Venous thromboembolic complications during the week of serial testing occurred in a single patient and in eight patients during 6 months' follow up, resulting in a cumulative rate of venous thromboembolic complications of 0.7% (95% confidence interval 0.3% to 1.2%). The mean number of extra hospital visits and additional tests required per initially referred patient was 0.8.
  
  
  CONCLUSIONS
  It is safe to withhold anticoagulant treatment from patients with clinically suspected deep vein thrombosis who have a normal result on compression ultrasonography at the time of presentation and at 1 week.
authors.affiliation: Istituto di Semeiotica Medica, University of Padua, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Cogo
authors.forename: A W
authors.initials: AW
authors.lastname: Lensing
authors.forename: M M
authors.initials: MM
authors.lastname: Koopman
authors.forename: F
authors.initials: F
authors.lastname: Piovella
authors.forename: S
authors.initials: S
authors.lastname: Siragusa
authors.forename: P S
authors.initials: PS
authors.lastname: Wells
authors.forename: S
authors.initials: S
authors.lastname: Villalta
authors.forename: H R
authors.initials: HR
authors.lastname: Büller
authors.forename: A G
authors.initials: AG
authors.lastname: Turpie
authors.forename: P
authors.initials: P
authors.lastname: Prandoni
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D005268:Femoral Vein / Q000000981:diagnostic imaging*; D005500:Follow-Up Studies; D006801:Humans; D008875:Middle Aged; D011152:Popliteal Vein / Q000000981:diagnostic imaging*; D011446:Prospective Studies; D013927:Thrombosis / Q000000981:diagnostic imaging*; D014463:Ultrasonography / Q000379:methods